The first case of human protothecosis caused by Prototheca zopfii in Japan

This report describes a fatal case Prototheca zopfii genotype 2 infection in an immunosuppressed patient. The patient was a 62-year-old housewife who presented general malaise in April 2011. Hairy cell leukemia was highly suspected. Chemotherapy was started because the patient developed severe pancytopenia in October 2011. Itraconazole capsules (100 mg/day) and trimethoprim (320 mg/day) plus sulfamethoxazole (1600 mg/day) combinations were orally administered for prophylaxis of fungal infections. Of BacT/ALERT 3D FA aerobic culture bottles and FN anaerobic culture bottles, only FA aerobic blood culture bottles produced positive reactions when the patient developed fever in January 2012. Gram-staining of blood culture bottles revealed Gram-negative elliptical sporangia. Culturing on Sabouraud dextrose agar produced smooth and creamy white, yeast-like colonies. Partial DNA sequences of the nuclear 18S rDNA and 28S rDNA D1/D2 domains of the isolated strain were identical to those of P. zopfii genotype 2. The MICs and minimal lethal concentrations of antifungals revealed that it was susceptible to amphotericin B and itraconazole. The patient died, at which time plasma (1 → 3)-β-D-glucan was positive (131 pg/mL).